Sealing devices for vending machines and like applications



March 23, 1965 F, ||E|L 3,174,383

SEALING DEVICES FOR VENDING MACHINES AND LIKE APPLICATIONS Filed June2l, 1961 United .States `Patent O 3 174 383 SEALING nnvrcns rionvnnnnnoMacnntns AND LIKE APPLECATEONS Friedrich Heil, Frankfurt am Main,Germany, assigner to Telefonbau und Normalzeit Sandali., Frankfurt amMain, Germany, a firm of Germany Fiied .lune 21, 1961, Ser. No. 118,719

Claims priority, application Germany, Apr. 26, 1961, ll 20, 62

This invention relates to sealing devices for vending machines and likeapplications.

It is` one object of the invention to provide improved tamper resistantsealing means for vending machines and like applications. y

It is another object of the invention to provide sealing means forvending machines Vand like applications which make it extremely ditcultfor unauthorized persons to get access to any particular piece ofequipment while making it relatively easy for authorized persons to getaccess to the particular piece of equipment.

Still another object of the invention is to providevending-machine-sealing-screw-means which are highly tamper resistantunless a special tool is applied for the removal thereof.

A further object of the invention is to provide a composite seal forvending machines and like applications wherein access to tamperresistant sealing-screw-means is normally precluded by a cap forming apart of an integral tamper resistant seal.

It has been proposed to seal vending machines by means of screws havinga head breaking off when subjected to a predetermined torsion. Openingof the vending machine involves removal of the shaft of the screw whichremoval must be effected by a drilling operation.

Such drilling operation is a relatively difficult achievement or taskfor any unauthorized person tampering with the vending machine. It is,however, also a relatively difiicult achievement or task for any personauthorized to obtain access to the vending machine.

It is, therefore, another object of the invention to provide an improvedscrew-seal predicated on the concept of precluding tampering by breakingoff the head of a sealscrew, but being more readily adapted to giveaccess to authorized persons than the aforementioned screw-seal.

The invention will be fully understood from the following descriptionwhen read in connection with the accompanying drawings, in which:

FIG. 1 is an isometric view of a longitudinal section of a sealembodying the present invention in the process of being established;

FIG. 2 is an isometric view of a longitudinal section of seal embodyingthe present invention upon being established; and

FIG, 3 is an isometric view of a longitudinal section of a sealembodying the present invention in the process of being removed.

Referring now to the drawings, and more particularly to FIG. l thereof,reference numerals 7, 8 and 4 have been applied to indicate threesuperimposed plates forming part of the base structure of a vendingmachine, eg., a postage meter. The bush 3, 5 forms likewise a part ofthe base stmcture. Plate 4 is provided with a tapped or screw-threadedhole 4a into which shaft 1 of a screw is inserted. The screw comprisingshaft 1 secures plates 7, it to plate 4 and thus prevents unauthorizedlremoval of plates 7, it from plate 4. Plates 7, 8 may be cover platescontrolling access to the setting mechanism of a postage meter, andplate 4 may be a portion of the housing for the setting mechanism ofsuch a meter. Base plate 7 is provided with a rectangular or squarecut-out or 3,174,383 Patented Mar. '23, 1965 ice recess 7a, and bush 3,5 includes a portion 5 rectangular o-r square in cross-section fittinginto the aforementioned cut-out or recessr7a. Thus rotation of bush 3, 5around the longitudinal axis thereof relative to base plate 7 iseffectively precluded. The portion of bush 3, 5 situated above baseplate 7 is substantially toroidal and delines a screw-head receivingchamber or cavity 17 having a bottom surface 17a. The end of bush 3, 5remote from plates 7, 3, i is provided with an undercut portion 18including a surface parallel to plates '7, 8, 4 and a conical surfaceflaring outwardly in downward direction, i.e., toward plates 7, d. Therectangular or square portion 5 of bush 3, 5 inserted into aperture 7adefines a cylindrical passage 19 for the shaft 1 of a sealing screw. Theentrance portion'Ztl of passage 19 is conical flaring outwardly inupward direction, i.e., away from plates 7, 8, 4, The screw-shaft 1supports a first screw-head Zhaving Va peripheral undercut edge 2aspaced from base struc ture 3, 5, 7, 8, 4. Screw-head 2 andthe abovebase structure, i.e., the bush 3, 5 thereof, define jointly an emp-tytoroidal space 6 recessed behind screw-head 2. Reference numeral 9 hasbeen applied to indicate a second screw-head projecting from the firstscrew-head 2 in a direction longitudinally of shaft 1. In the embodimentof the invention shown in FIG. l both screw-heads 2, 9 are in the shapeoff inverted frustum cones. As shown in FIG. 1 screw-head 2 isaccommodated `in screw-head receiving chamber 17, whereas screw-head 9projects beyond chamber or cavity 17 exposing its groove 9a for readyinsertion of a screw-driver. Reference numeral 1t) has been applied toindicate the junction between screw-heads 2 and 9. This junction is apoint of minimal torsional strength to cause breaking of the screw 1, 2,9 at junction 11i when screw-head 9 is subjected by a screw-driver orlike tool to a predetermined torsion. In the embodiment of the inventionthe weak point 1li of screw 1, 2, 9 has a smaller cross-sectional areathan any other point of screw-head 2 and any other point of screwhead 9.The upper circular surface 2b of screw-head 2 is not provided with anyrecess giving access to any kind of screw-operating tool such as, forinstance, a screwdriver. Therefore, after head 9 has been broken off bya person authorized to get access to the vending or like machine, shaft1 cannot be-or can hardly be-unscrewed by an authorized person intendingto improperly obtain such access. After head 9 has been 4broken off acap or cover plate 11 is inserted into the open frontend of bush 3, 5.Cap or cover plate 11 is made of a soft metal as, for instance, lead.When pressure is applied to the front end of plate 11 the same expandsand enters into the undercut portion 18 of bush 3, 5, thus forming asecondary seal tending to preclude access to the screw-head 2 inscrew-head chamber 17. Seal plate 11 is also an indicator showingwhether an unauthorized person has attempted to tamper with the Vendingmachine. When expanding cap 11 its rear side may rest against screwhead2 thus forming a boss for expanding cap 11,

FIG. 2 shows the machine as being protected completely againstunauthorized manipulation by means of sealing screw 1, 2 and sealing capor plate 11.

A person authorized to get access to the vending machine may firstremove seal or cap 11, and then remove screw 1, 2 by means of a specialtool adapted to make one or more appropriate indentations intoscrew-head 2. Such a tool may be in the form of a chisel 12 shown inFIG. 3 including a pair of spaced prongs 13, 14 having sharp cuttingedges. These prongs are adapted to pierce the screw-head 2 and to enterthe toroidal empty space recessed behind top surface 2b of screw-head 2.Thus two slots 15, 16 are formed in screw-head 2. Now screw 2, 1 mayreadily be' removed either by turning chisel 12,

or substituting a screwdriver for chisel 12 having a geometry similar tothat of chisel 12, i.e. including a pair of spaced prongs adapted toenter into slots 15, 16 in screw-head 2.

It will be understood that I have illustrated and described herein apreferred embodiment of the invention, and that various alterations maybe made in the details thereof without departing from the spirit andscope of the invention as defined in the appended claim.

I claim:

A sealing device for vending machines and like applications comprising abase structure including a base plate, a recess in said base plate, abush having a first portion projecting into said recess in said baseplate and a second portion situated above said base plate and forming ascrew-head receiving cavity having a lateral wall defining a circularshoulder, said cavity further having a bottom surface including asurface inclined to the axis of the bush, means for precluding a rotarymotion of said bush around the axis thereof relative to said base plate,a screw including a screw-threaded shaft projecting through said bushinto a portion of said base structure, a iirst screwhead on said shaftsubstantially in the shape 0f an inverted frustum of a conecomplementary to said seated on said inclined surface, a secondscrew-head projecting from said rst screw-head in a directionlongitudinally of said shaft, the point of junction between said rstscrewhead and said second screw-head having a smaller crosssectionalarea than any other point of said first screwhead and any other point ofsaid second screw-head, and said first screw-head having a base surfaceand part of said cone situated in a plane above said bottom surface ofsaid cavity to provide a space between said irst screwhead and saidbottom surface and below said shoulder dened by said lateral wall ofsaid cavity, said base surface being substantially smooth anduninterrupted.

References Cited in the le of this patent UNITED STATES PATENTS 141,908Ackerman Aug. 19, 1873 461,523 Phelps Oct. 20, 1891 2,054,060 MorrisSept. 8, 1936 FOREIGN PATENTS 18,369 Great Britain Aug. 16, 1906 684,821Great Britain Dec. 24, 1952 31,850 Norway Feb. 28, 1920 `ERNEST W..SWIDER Anesting Officer UNITED STATES PATENT oFFlCE CERTIFICATE 0FCORRECTION Patent No. 3,174,383 'March 23, 19.65

Friedrich Heil l It is hereby certified that error appears invtheabovenumbered patent reqlrng correction and that the said Letters Patentshould read as corrected below Column 3, line 24,. for "said" read fandSigned and sealed this` 24th: day of August 1965'.

(SEAL) Attest:

, EDWARD J. BRENNER Commissioner of Patents

